This invention relates to valves which may be characterized as having a short stroke and high volumetric flow capability. More particularly, the invention relates to electromagnetically actuated valves having a multi-orifice valving means to controllably open and close a plurality of fluid flow passages therein.
Electromagnetically actuated valves often comprise a housing having at least one fluid flow passage therein and contain an electromagnet and a movable armature which is maintained in a variable spaced relationship relative to the electromagnet. These valves often contain a valving means comprising a stationary valve seat and a valve plate operatively connected to and movable with the armature to controllably open and close a single fluid flow passage in the valve plate in response to the command signals input to the electromagnet. It is highly advantageous to have a valve that has a short stroke (ie limited armature movement) and a high fluid flow capability. The high flow capability implies the use of a large flow area associated with the valving means. As an example consider a valve that has a longitudinal stroke of length, x, and is further characterized as having a circular fluid flow passage of radius, r, in its valve seat. It can be shown that the flow area, that is the circumscribing area surrounding the perimeter of the flow passage between the valve seat and the valve seat is 2.pi.rx. High flow areas can be achieved by increasing the radius r. The distinct disadvantage of increasing the flow area in this manner is that as the size of the opening is increased the area remaining for sealing is substantially reduced. This reduced sealing area in concert with large fluid pressure forces encourages deformation of the sealing area which in turn increases leakage flow. Furthermore by increasing the dimensions of the fluid flow passage and hence decreasing the remaining structure the strength of the valve seat is reduced.